Tooth migration
In dentistry, tooth migration is the change in position or displacement of teeth or groups of teeth. It represents a special form of tooth ectopia . The harmonic occlusion of the dentition can become unstable due to tooth migration or tooth displacement .
Causes of tooth migration
The physiological and pathological causes of tooth displacements and changes in position are diverse.
Periodontal disease
The most common causes of tooth migration are loosening of the teeth in periodontal diseases . Often this tooth migration occurs even before noticeable tooth loosening . The tooth-retaining apparatus , by means of which the teeth are anchored in the jawbone, is already clearly destroyed, the bony anchoring of the roots is insufficient. A typical picture is the fanning out (tilting) of the six upper front teeth in the vestibular direction (towards the oral vestibule ), which tilt forwards due to tongue pressure or due to the swelling of periodontal tissue during the active inflammatory phase. This increases the radius of the dental arch and there are characteristic gaps between the maxillary anterior teeth . This tooth migration is further promoted by the pressure of the lower front teeth from the palatal area, especially in the case of a so-called deep bite . Pronounced hyperplasia , for example after taking hydantoin , can cause tooth migration.
Tooth loss
Another cause of tooth migration or tooth displacement can also be tooth loss , for example due to extractions that have become necessary (tooth removals). If the resulting tooth gap remains unsupported, the neighboring teeth can gradually move towards the gap in the sense of a compensatory gap closure. Alternatively, the neighboring teeth may tilt.
Orthodontic Therapy
As part of an orthodontic treatment, adjacent teeth that have not yet erupted are physically moved towards the extraction gap in the context of an iatrogenic tooth displacement during extraction therapy - without tilting. A systematic extraction of the first molar takes place shortly before the second molar penetrates. The tooth movement subsides .
Physiological tooth migration
The dynamic occlusion (bite) in connection with the mobility of the teeth leads to physiological abrasion ( abrasion dentium ) of the approximal contacts (the lateral punctiform contact points) of the tooth crowns. As a result, the contact points become slightly flat over the years due to wear, which slightly shortens the length of the entire dental arch by 2 to 5 mm and leads to a mesial drift of the teeth.
Elongation
After an extraction, elongation can be observed in the opposing jaw. This elongation represents a displacement of teeth - by a few millimeters - into the gap between the teeth of the opposing jaw. Although the term "tooth lengthening" is colloquially known, the teeth only appear to be longer because only the visible part of the tooth is enlarged due to the vertical displacement of the tooth . Elongations are particularly noticeable in the upper jaw.
Occlusal drift
The occlusal drift is intended to compensate for the loss of enamel on the cusps of the chewing surface, which is caused by abrasion through years of chewing activity. The apical root cement thickens due to cement deposits at the root tip. At the same time, bone is built up at the bottom of the alveolus through newly formed bone substance.
Parafunctions
Another cause of tooth migration can be parafunctions (malfunctions) such as bruxism (teeth grinding ), especially with unfavorable one-sided pressure. So-called "habits" (bad habits, harmful movement patterns) in addition to teeth grinding are also possible causes of tooth migration, such as intense, frequent tongue clenching, lip pressure or finger sucking, which affects the position of the teeth. If the bone is exposed to too much pressure, the jawbone breaks down in these areas and the tooth moves in the direction of the breakdown. This takes place faster in the upper jaw than in the lower jaw due to the different bone structure .
Incorrect contacts
Incorrect contacts, for example caused by occlusally defective dentures, can trigger tooth migration of the antagonists (opposing teeth). Incorrect contacts must be corrected by grinding in the bit.
Cysts and tumors
By extensive odontogenic cyst , Nonodontogenic cysts , abscesses or tumors may result in tooth migration when pressure is exerted on the tooth roots through it.
Diagnosis
Tilted or elongated (seemingly elongated) teeth are characterized in the diagnostic chart with arrows that indicate the direction of kipping, elongation or tooth migration: → or ←, ↑ or ↓. A gap closure is indicated by two opposite brackets) (. If the gap has been closed by tooth migration, additional arrows are indicated before and / or after the brackets: →) (←.
In the following example, a gap closure by tooth movement is shown after the extraction of the premolars 14, 24, 34 and 44, which is necessary for orthodontic reasons . A gap was closed between tooth 18 and 16 when tooth 17 was missing, in that tooth 18 had migrated in the mesial direction due to tooth migration .
| top right | top left | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| →) ( | ) ( | ) ( | Finding | |||||||||||||
| 18th | 17th | 16 | 15th | 14th | 13 | 12 | 11 | 21st | 22nd | 23 | 24 | 25th | 26th | 27 | 28 |
Tooth designation |
| 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | |
| ) ( | ) ( | Finding | ||||||||||||||
| bottom right | bottom left | |||||||||||||||
Demarcation
- In the course of tooth eruption ( dentition ), there is naturally also a change in the position of the tooth, which lasts until the tooth and its neighboring teeth have adjusted to the row of teeth. (first and second physiological bite elevation ). This change in the position of the teeth is not counted as tooth migration.
- The displacement of teeth as part of orthodontic therapy to change the position of the teeth (change in tooth position) is not referred to as tooth migration, but rather as tooth movement .
- A displacement of teeth in the context of trauma, which usually occurs as an intrusion , does not constitute tooth migration.
- Tooth migration (tooth movement) is also to be distinguished from physiological or pathological tooth mobility ("wobbling"). Tooth loosening (1st to 3rd degree) usually occurs as a result of periodontal disease or tooth trauma.
Prevention and treatment
By timely incorporation of dentures in the form of a fixed bridge, an implant or removable dentures such as a partial denture or a gap holder in the mixed dentition, tooth migration can be prevented. However, this is only useful for tooth migration that is not caused by periodontal disease. In the case of periodontal tooth migration, periodontal treatment is indicated, which is intended to bring about a reduction in inflammation and bone regeneration of the diseased bony periodontal apparatus. The splinting of loosened teeth by splinting with composite , possibly reinforced with wire or with special metal splints, which was common in earlier years , has been abandoned because this did not improve the prognosis of the tooth.
An orthodontic treatment of tooth migration is under the cash-dental relatively rare supply in Germany. Orthodontic treatment of the migration of the teeth is usually followed by a supply of dentures. The orthodontic treatment does not necessarily have to aim at reversing the tooth migration, but is usually limited to straightening up tilted teeth in order to enable a prognostically more favorable axial load by the bridge or prosthesis to be made afterwards. If no dentures are made after an orthodontic treatment, a retainer is usually used to permanently stabilize the situation.
forecast
The prognosis can vary widely. As part of an overall prosthetic planning, the extraction of displaced / tilted and mostly periodontally damaged teeth can be indicated.
When the teeth migrate in a closed row of teeth, normal contact with the neighboring teeth is lost, which can trigger the subsequent shifting of further neighboring teeth as a chain reaction.
Therapy costs
In Germany, the expected migration of teeth after an extraction triggers the insured person's entitlement to benefits from his statutory health insurance as part of contract dental care. The relevant guidelines state: “Dentures are indicated if one or more teeth are missing or destroyed and if the functionality of the chewing organ is impaired or threatens to be impaired, e. B. by tooth migration or tilting. "
Teeth migration in animals
In contrast to humans, in whom teeth migrate mainly in the mesial direction, in rats a distal migration of the teeth is observed in the event of a tooth loss. Changes in the teeth of horses take place throughout their life, such as constant advancement of the teeth from their alveoli. Depending on the author, this advance is 2-4 mm on the incisors and 2-9 mm on the molars.
Individual evidence
- ^ Walter Hoffmann-Axthelm : Lexicon of dentistry. Berlin 1995, 6th edition, Quintessenz Verlag, p. 817, keyword: tooth migration. ISBN 3-87652-609-4 .
- ^ Jean-François Roulet, Stefan Zimmer: Volume 16: Prophylaxis and preventive dentistry . Georg Thieme Verlag, December 18, 2002, ISBN 978-3-13-158351-2 , p. 204–.
- ^ Herbert F. Wolf, Edith M. Rateitschak, Klaus H. Rateitschak: Parodontologie . Georg Thieme Verlag, 2004, ISBN 978-3-13-655603-0 , p. 106–.
- ↑ Wolfgang Gühring, Joachim Barth: Anatomie: special biology of the masticatory system . Verlag Neuer Merkur GmbH, 1992, ISBN 978-3-921280-84-3 , p. 212.
- ^ Rudolf W. Ott: Clinic and Practice Guide Dentistry . Georg Thieme Verlag, 2003, ISBN 978-3-13-131781-0 , p. 448.
- ↑ Ernst Lauterbach: Dictionary DENTAL MEDICINE. Werner Dausien, Hanau, 1992, p. 1819, keyword: tooth migration. ISBN 3-7684-9249-4 .
- ↑ Sture Nyman and Jan Lindhe, A Longitudinal Study of Combined Periodontal and Prosthetic Treatment of Patients With Advanced Periodontal Disease , Journal of Periodontology , April 1979, Vol. 50, No. 4, pp. 163-169, doi: 10.1902 / jop.1979.50.4.163 . Retrieved May 5, 2017.
- ↑ Guideline of the Federal Joint Committee for a sufficient, appropriate and economical contract dental care with dentures and dental crowns (dentures guideline), December 8, 2004, published in the Federal Gazette 2005 (p. 4094), came into force on January 1, 2005 May 2017.
- ^ Thomas M. Graber, Brainerd F. Swain: Basics and modern techniques of orthodontics . Quintessence, 1989, ISBN 978-3-87652-214-2 . , P. 161.
- ↑ Stefanie Huthmann, Position of the horse molars in the jaw and calculation of the chewing forces occurring on the molars using a biomechanical model , dissertation 2007. accessed on May 7, 2017.
